1. Field
The invention is in the field of fluid control valves, pressure reducing valves, and pressure relief valves for pipe lines, all operating by means of elastomeric sleeve diaphragms.
2. State of the Art
There are diaphragm sleeve valves currently used to control fluid flow in pipe lines. These valves require the tying or securing of the ends of their sleeve diaphragms. Current sleeve valve designs require the valves to be taken out of the line when replacing their sleeve diaphragms. These valves are designed with slots of very small size, and therefore, can pass only small sized particles in the fluid. The inventor is not aware of any valve using a bell type diaphragm.
The present invention provides a valve which can accommodate larger sizes of debris, and can also accommodate more than one diaphragm in the same valve, which increases the capacity of the valve. Preferably, the ends of the diaphragms are kept free, to keep them from stretching, thus increasing the useful life of the diaphragms; but ends can be tied to the valve body if desired or required.
This invention provides a bell type diaphragm which simultaneously puts the diaphragm in stretch and compression mode, which mitigates the effect of the harmful stretch. It also divides the diaphragm into two sections, where the first section acts as a check valve and the second section acts as a regular valve. Thus, two valves (in the same valve) are provided with one diaphragm. Since each of the said two sections of a diaphragm requires half of the fluid volume usually required by conventional sleeve valves, both sections can be operated with twice the opening and closing speed of conventional sleeve valves. To meet some requirements, the invention provides a faster shut off valve/control valve/check valve combination.
In some applications where the valve""s handling of debris is a concern, arcuate platens, made of rigid metal, plastic, or reinforced rubber, are placed inside the diaphragm or around the diaphragm, to cover wider slots than slots commonly used. These slots are made in the cylindrical walls of the inlet and outlet chambers. Thus, this invention provides diaphragms which can accommodate increased slot sizes, thus allowing a valve to accept the passing of debris of very much greater size than is possible with current valves.
The present valve also can function as an air and vacuum valve.
There is demand in the industry for high capacity automatic control valves with less maintenance. Elastomeric diaphragm sleeve valves require less maintenance but their capacity as shut of valves is limited, and frictional losses through the valves are high. In one embodiment, the present valve reduces frictional losses by installing at least two concentric diaphragms in the same valve, where inlet fluid is divided between two or more diaphragms. The fluid is controlled by said diaphragms, and these diaphragms may be controlled by a single pilot valve. By using two diaphragms, the capacity of the valve is increased and frictional losses are reduced by reducing the over-all velocity of the fluid through the valve. The valve may be designed such that each of the concentric diaphragms in the valve will require different initial opening pressures. Thus, when one diaphragm is open, the other diaphragm will remain in closed position until its opening pressure is reached. Thus, the scope of the valve is enhanced, since the valve can be made to operate to handle different scenarios.
Like butterfly and ball valves, the two or more diaphragms in the same valve handle much higher fluid volume than conventional sleeve valves. Also, the double diaphragm design cuts the length and stroke of each diaphragm. This reduction in diaphragm length cuts the overall length and weight of the valve, compared to conventional sleeves valves of equal fluid capacity.
According to the invention, a multi-diaphragm valve includes a valve body which accommodates a bell type or bell shaped open ended elastomeric diaphragm. The Bell type diaphragm includes a central radially outwardly extending hump, and legs extending axially from opposite sides of the hump. In effect, this is a composite of two diaphragms joined by the hump. Each leg is a cylindrical portion of the diaphragm and in effect, acts as a separate diaphragm in the valve, thus providing a multi-diaphragm valve. The first leg is seated around the outside of an interior wall forming a cylindrical inlet chamber and the second leg is seated around the outside of an interior wall forming a cylindrical outlet chamber, both inside the valve body. Both chambers have dead end partition plates creating closed ends for the interior chambers which meet face to face at the center of the valve body. Said diaphragm legs around said seats preferably will be inclined toward the center of the valve. The legs of the diaphragm are provided snug fit by the outward pressure exerted by the hump of the diaphragm. From here on, the word diaphragm will be understood as an open ended multi-diaphragm of a bell shape, having two cylindrical or two inclined legs, inclining toward the center of the valve body, where legs are mounted around two corresponding seats separated by dead end partition plates in said inlet and outlet chambers. The valve of the invention provides a valve body to accommodate one or more diaphragms, concentric to the longitudinal axis of the valve. Preferably, the ends of the diaphragm or diaphragms are kept free, to relieve excessive stretch from the ends. The bell type diaphragm is divided into two sections; the first section has the first leg, and the second section has the second leg. The two said legs are separated by the circular hump of the diaphragm, where said hump is positioned centrally around said dead end partition plates, and creates a hollow circular cavity around said plates. The valve can be opened or closed much faster than conventional sleeve type valves. The first section or leg of the bell type diaphragm is provided with a plurality of openings in the upstream wall of the hump, to make the first section of the diaphragm function as a check valve. The first section of the diaphragm is installed up stream in the valve. The first section of the diaphragm also provides means for the pilot valve to access fluid from the inlet of the valve. The valve can function as a flow control valve, a pressure reducing valve, a check valve, a pressure relief valve, and an air vacuum valve.
The legs of the diaphragm can be provided with arcuate platens. Whether or not said platens are provided in or around the legs of the diaphragm or diaphragms, depends on the required function which the valve will be required to fulfill. The thickness of the elastomeric diaphragm need not be uniform, it can vary from section to section in legs or in the hump to perform the intended function of the valve. The variable thickness of the diaphragm becomes useful in the design of the air vacuum valve where atmospheric pressure should be able to open the valve to beak the vacuum.
The valve of the invention includes a composite body divided into two parts; the first part and the second part. The first part is upstream, and has an interior cylindrical chamber that functions as an inlet chamber with a cylindrical inlet opening to receive fluid from the inlet pipe of the pipe line in which the valve is installed. It also has a blocking means partition plate P1 to close the end of the chamber and divert the fluid through a plurality of radial slots upstream from the plate extending through the interior wall forming the interior inlet chamber. The second part has an interior cylindrical chamber, similar to the first part, that functions as an outlet chamber; the difference being that the chamber of the second part is approximately a mirror image of the chamber in the first part. The outlet chamber receives fluid from the first part which flows through a plurality of radial slots extending through the interior wall forming the interior outlet chamber. The outlet chamber has a cylindrical outlet opening to provide fluid from the outlet chamber to the outlet pipe of the pipe line in which the valve is installed. The partition plate P2 of the second part closes the end of the outlet chamber and abuts said partition plate P1 when the parts are joined, where P2 blocks reverse flow of fluid from downstream of the valve. Farther away from the partition plates P1 and P2, and also farther away from the radial slots in the two interior walls forming said interior cylindrical chambers, two integrally constructed conic walls W and W1 (preferably having equal inclines), emerge from the walls of said interior cylindrical chambers to form outer chambers and meet in the central transverse vertical plane to the longitudinal axis of the valve body. The walls W and W1 are provided with radial flanges f1 and f2 at their extremities. Once the diaphragm or diaphragms are attached to flange f1, and loaded on the seat of the first part of the valve, the two flanges are joined by means of bolts or by means of an integral coupling provided on one of the two flanges. Thus, the diaphragm for the valve is enclosed in a trapezoidal circular diaphragm chamber formed by joining the outer chambers of the two parts. To attach the two ends of the valve to inlet and outlet pipes, the caming jaws of couplings invented by the inventor under Ser. Nos. 5,387,017 and 5,868,441 may be used. The diaphragm or diaphragms can be pre-loaded or can be loaded into the valve body at site.
The fluid diverted by P1 in the first part, passes through said radial slots of the interior wall of the first part, and is controlled by the first section or leg of the diaphragm. The fluid then passes through the diaphragm chamber around P1 and P2 and through the radial slots of the interior wall of the second part into the interior cylindrical outlet chamber. Flow of fluid through the redial slots of the second part is controlled by the second section or leg of the diaphragm. The fluid flows from the outlet chamber into the outlet pipe.
The pressure reducing or pressure relief valves of this invention are controlled by conventional pilot valves. When the valve is used as a shut off valve, a pilot valve and needle valve are not required. When the valve is used only as a check valve, no control valves are needed. Only three ports V1, V3, and V6 will be connected by tubes common to all three said ports.
In order to increase the flow of fluid through the valve without increasing the friction substantially, two parallel flow paths and control diaphragms may be provided. In such instance, a second interior cylindrical chamber forming a second inlet chamber is provided in the first part in flow communication with the inlet chamber described, which can be referred to as the first inlet chamber and a second interior cylindrical chamber forming a second outlet chamber is provided in the second part in flow communication with the outlet chamber described, which can be referred to as the first outlet chamber. A second diaphragm chamber is also formed with a second diaphragm to provide a controlled flow path between the second inlet chamber and the second outlet chamber similar to the first diaphragm chamber and diaphragm already described. The second chambers will generally be concentric with the first chambers.
Seals and gaskets are provided against unwanted leakage inside the valve, and from the valve to the outside environment.
It should be pointed out that various means other than described above can be adopted to join flanges f1 and f2 or connecting means other than flanges can be used to connect the valve parts; as can various connecting means be used other than flanges 20 and 20A to connect the valve to the inlet and outlet pipes.
In a preferred embodiment of the valve, the valve is connected to the inlet and outlet pipes in a manner which allows the valve parts, when separated, to slide along the pipe a distance sufficient to allow the diaphragm to be removed from the diaphragm chamber and replaced without removing the valve parts from the pipe, or for other maintenance of the valve. When the valve parts slide along the pipe, the ends of the pipes slide into the interior cylindrical chambers. The travel of the parts along the pipe is limited by the distance the pipe ends can slide into the interior chambers.